A light control method in which a PWM signal as a light control instruction signal is input to control the light of a light source in accordance with the on-duty of the signal, or a light control method in which a 0 to 10 V control signal as a light control instruction signal is input to control the light of a light source in accordance with the analog value of the signal has been known from the past.
On the other hand, as an illumination control system, a system (illumination control system) that controls an illumination device by transmitting a signal compliant with the DALI (Digital Addressable Lighting Interface) standard as a light control instruction signal has recently been developed mainly in Europe.
In this respect, Japanese Unexamined Patent Application Publication No. 2013-4484 proposes an illumination control system compliant with the DALI standard.